Surgical filament snare assemblies

ABSTRACT

A surgical filament snare assembly including an anchor capable of being fixated in bone and having a filament engagement feature. A first filament has a noose on a first portion of at least a first limb and has a second portion connected to the filament engagement feature of the anchor. Preferably, at least one free filament limb, which in some embodiments is a length of the first filament and in other embodiments is a second filament, is capable of being passed through tissue to be repaired and has at least one end passable through the noose to enable incremental tensioning of the tissue after the anchor is fixated in bone. The noose strangulates the free filament limb when tension is applied to at least one of the free filament limb and the noose.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to filament assemblies for securing tissue to bone and more particularly to adjustable tensioning of tissue independent of anchor fixation.

2. Description of the Related Art

A common injury, especially among athletes, is the complete or partial detachment of tendons, ligaments or other soft tissues from bone. Tissue detachment may occur during a fall, by overexertion, or for a variety of other reasons. Surgical intervention is often needed, particularly when tissue is completely detached from its associated bone. Currently available devices for tissue attachment include screws, staples, suture anchors and tacks.

Arthroscopic knot tying is commonly practiced in shoulder rotator cuff and instability procedures. Typically, an anchor loaded with suture is attached to bone first. The suture is normally slidably attached to the anchor through an eyelet or around a post, such that a single length of suture has two free limbs. One limb of the suture is passed through soft tissue to be repaired such as a tendon or labrum. The two ends of the suture are then tied to each other, thereby capturing the soft tissue in a loop with the anchor. Upon tightening the loop, the soft tissue is approximated to the bone via the anchor.

Surgeons typically tie the suture ends by first placing a surgical sliding knot such as the Tennessee Slider or Duncan Knot. After tightening the loop, a number of additional half hitches or other knots are tied. The additional knots are needed because a conventional sliding knot does not provide the necessary protection against loosening or slippage, especially when tension is placed primarily on the limbs of the loop. Generally accepted practice is to follow the sliding knot with at least three reversed half hitches on alternating posts of the suture.

Before one or more half hitches or other knots can be added to the sliding knot, however, there exists a potential for the sliding knot to slip, that is, for the loop to enlarge as the tissue places tension on the loop. This has been referred to as “loop security” and can reportedly occur even in the hands of very experienced surgeons. Sometimes, even fully-tied knots may slip. Further, the overall size of a conventional knot can be obstructive or intrusive, especially in tight joints, which may damage cartilage or other tissue by abrasion with the knot.

Suture anchor systems with sliding and locking knots for repairing torn or damaged tissue include U.S. Pat. No. 6,767,037 by Wenstrom, Jr. Other suture anchor systems suited especially for meniscal repair are disclosed in U.S. Pat. No. 7,390,332 by Selvitelli et al. and are utilized in the OmniSpan™ meniscal repair system commercially available from DePuy Mitek Inc., 325 Paramount Drive, Raynham, Mass. 02767.

There are a number of suture implant systems which proclaim to be “knotless”, that is, to not require a surgeon to tie a knot during surgery. Many such systems control tension on tissue by the depth to which an anchor is driven into bone. U.S. Pat. Nos. 5,782,864 and 7,381,213 by Lizardi disclose certain types of suture anchors which capture a fixed-length loop of suture. Adjustable loop knotless anchor assemblies utilizing an anchor element inserted into a sleeve are described by Thal in U.S. Pat. Nos. 5,569,306 and 6,045,574 and in U.S. Patent Application Publication No. 2009/0138042. Other systems having clamps or other locking mechanisms include U.S. Pat. No. 5,702,397 by Goble et al. and U.S. Patent Application Publication No. 2008/0091237 by Schwartz et al.

It is therefore desirable to have robust yet adjustable fixation of tissue while minimizing both the number and size of knots to be tied by a surgeon, especially during arthroscopic repair procedures.

SUMMARY OF THE INVENTION

An object of the present invention is to meet or exceed the tissue tension control and holding power of currently available suture anchor assemblies for tissue repair procedures while reducing the number of half hitches or other knots to be tied by a surgeon.

Another object of the present invention is to reduce the size of the finished knot for the assembly.

A still further object is to simplify the overall knot tying process for the surgeon while providing enhanced loop security and knot security

Yet another object of the present invention is to provide incremental tensioning after anchor fixation.

This invention features a surgical filament snare assembly including an anchor capable of being fixated in bone and having a filament engagement feature. A first filament has a noose on a first portion of at least a first limb and has a second portion connected, including slidably or fixedly connected, to the filament engagement feature of the anchor. The noose, such as one or more half-hitches or a hangman-type noose, is capable of receiving at least one end of a free filament limb and strangulating it when tension is applied to at least one of the free filament limb and the noose.

In preferred embodiments, at least a first free filament limb, which in some embodiments is a length of the first filament and in other embodiments is a second filament, is capable of being passed through tissue to be repaired and has at least one end passable through the noose to enable incremental tensioning of the tissue after the anchor is fixated in bone. In some embodiments, the noose is retractable toward the anchor. At least one tube may be included to assist passing the free filament limb through the noose.

In certain embodiments wherein the noose is formed from at least one half hitch, the assembly includes at least two tubes capable of being removably inserted into different loops of the half hitch to provide passages for two ends of free filament limbs. In some embodiments, the tubes are joined together and have at least one handle for manipulating the tubes. Preferably, each tube is slotted to facilitate removal of the free filament limbs from the tubes.

This invention also features a surgical suture snare assembly having an anchor capable of being fixated in bone and having at least one passage and a suture engagement feature. A first suture has a noose on a first portion of at least a first limb and has a second portion passing through the passage and connected to the suture engagement feature of the anchor. A second suture has at least a first free suture limb which is capable of being passed through tissue to be repaired and has at least one end passable through the noose to enable incremental tensioning of the tissue after the anchor is fixated in bone, the noose strangulating the free suture limb when tension is applied to at least one of the free suture limb and the noose.

Yet another feature of this invention is a surgical suture snare assembly having an anchor capable of being fixated in bone and having at least one passage and a suture engagement feature. A first suture has a noose on a first portion of at least a first limb and has a second portion passing through the passage and connected to the suture engagement feature of the anchor. The first suture further has at least a first free suture limb which is capable of being passed through tissue to be repaired and has at least one end passable through the noose to enable incremental tensioning of the tissue after the anchor is fixated in bone, the noose strangulating the free suture limb when tension is applied to at least one of the free suture limb and the noose.

A still further feature of this invention is a method of surgically repairing tissue, including selecting an anchor capable of being fixated in bone and having a filament engagement feature. A first filament is selected having a noose on a first portion of at least a first limb and having a second portion connected, including slidably or fixedly connected, to the filament engagement feature of the anchor. The method further includes fixating the anchor in bone, selecting at least a first free filament limb, and passing it through the tissue to be repaired. At least one end of the free filament is passed through the noose, and the tissue is tensioned as desired after the anchor is fixated in bone, the noose strangulating the free filament limb when tension is applied to at least one of the free filament limb and the noose.

In some embodiments, the free filament limb is selected from a length of a second filament. In one embodiment, the second filament includes a second free filament limb which is also passed through the noose such that the tissue is captured between the first and second free filament limbs. In certain embodiments, tension is also applied to the noose by retracting it toward the anchor.

In other embodiments, the method further includes placing a stopper element on the free filament limb after it is passed through the noose to inhibit withdrawal of the free filament limb from the noose. In some embodiments, a knot is tied and slid toward the noose to serve as the stopper element. At least one tube may be removably inserted into the noose to assist passing the free filament end through the noose. In certain embodiments, the noose is formed from at least one half hitch having at least three openings. At least two tubes are removably inserted into different openings of the half hitch to provide passages for at least two ends of free filament limbs. At least two free filament ends are passed through different openings in the half hitch.

BRIEF DESCRIPTION OF THE DRAWINGS

In what follows, preferred embodiments of the invention are explained in more detail with reference to the drawings, in which:

FIG. 1 is a schematic side view of a surgical filament snare assembly according to the present invention having an anchor and a noose;

FIG. 1A is a schematic side view of a hangman-type noose and FIG. 1B is such a view of a half-hitch noose to be utilized according to the present invention;

FIG. 2 is a schematic side view of the assembly of FIG. 1 removably connected with a cannulated driver for initially fixating the anchor with a threader loop passed through the noose;

FIGS. 3-10 are schematic side views illustrating a process for capturing and tensioning tissue to the surgical filament snare assembly according to the present invention, with FIG. 8A providing an example of a stopper knot shown in FIGS. 8, 9 and 10;

FIGS. 11 and 12 are perspective views of an alternative half-hitch noose in which multiple openings are utilized to strangulate two or more free filament limbs;

FIG. 13 is a perspective view of tubes to assist threading of free filament limbs through noose openings of FIG. 11;

FIG. 14A is a perspective view of a double-barreled, slotted threader device;

FIG. 14B shows the device of FIG. 14A being utilized to thread a noose;

FIGS. 15-19 illustrate different snare assemblies with retractable-noose configurations according to the present invention;

FIG. 20 is a schematic top view of multiple filaments that are passed through a single noose of a snare assembly according to the present invention;

FIG. 21 is an enlarged view of one construction of the configuration shown in FIG. 18;

FIGS. 22-27 are schematic side views of the snare assembly of FIG. 18 utilized with another anchor placed through tissue to be repaired; and

FIG. 28 is a perspective view of a snare assembly according to the present invention having a cannulated suture anchor.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

This invention may be accomplished by a surgical filament snare assembly including an anchor capable of being fixated in bone and having a filament engagement feature. A first filament has a noose on a first, proximal portion of at least a first limb and has a second portion connected, including slidably or fixedly connected, to the filament engagement feature of the anchor. The noose, such as one or more half-hitches or a hangman-type noose, is capable of receiving at least one end of a free filament limb. The noose strangulates the free filament limb when tension is applied to the noose, to the free filament limb, or to both.

In preferred constructions, at least a first free filament limb, which in some constructions is a length of the first filament and in other constructions is a second filament, is passed through tissue to be repaired and has at least one end passable through the noose to enable incremental tensioning of the tissue after the anchor is fixated in bone.

Surgical filament snare assembly 10, FIG. 1, has an anchor 12 and a first filament 14. In this construction, anchor 12 defines an internal passage 16 with a restricted opening 18 at its distal end 20 which serves as a filament engagement feature. At least one bone-engaging feature 22, such as an external rib or helical thread, is located on the outer surface of anchor 12 between distal end 20 and proximal end 24.

First filament 14 has a noose 30 at its proximal end and a fixed knot 32 at the distal end of filament post or stem 15 which interacts with restricted opening 18 to retain filament 14 in a fixed, permanently attached position. This arrangement may be referred to as the first filament 14 connected with the filament engagement feature 18, which includes the phrase passing through the filament engagement feature 18. Many conventional knots, such as a mulberry knot, can be utilized for fixed knot 32 as long as knot 32 has sufficient bulk to prevent pull-through at clinically desired tensions on noose 30. A number of other types of filament engagements are described below. Stem 15 is kept as short as possible to maintain noose 30 close to anchor 12 even after it is collapsed as described below.

A well-known noose knot 33 is illustrated in FIG. 1A in which first filament 14 a has a hangman-type noose 30 a at its proximal end and a fixed knot 32 a at the distal end of stem 15 a. Noose 30 a has sliding noose knot 33 and defines an opening 34. Noose knot 33 is tied by forming a flattened “S” or “Z” shape at the proximal end of filament 14 a to form a large proximal loop to serve as the noose opening and a small loop spaced from the large loop. The doubled filament limbs are wrapped with the terminal end, also known as the working end. After typically four to eight wrapping turns, the terminal end is tucked through the small loop and trapped by pulling on whichever of the limbs of the large loop closes the small loop.

An alternative, simpler noose is illustrated for first filament 14 b, FIG. 1B, having a half hitch 35, also referred to as a simple or overhand knot, tied to form noose 30 b in the middle of filament limbs 36 and 38. Multiple openings are created by the loops in half hitch 35 as described in more detail below, although central opening 37 is shown as a large single opening in FIG. 1B. First filament limbs 36 and 38 are folded around half hitch 35 to form a double-stem arrangement, and the distal ends of first filament limbs 36 and 38 are joined in knot 32 b after being passed through a suitable filament engagement feature on an anchor.

Noose efficiency is defined herein as the strangulation strength per unit tension applied on the noose, either by pulling on the filament on which the noose is tied or which otherwise carries the noose, or by pulling on one or more strands or limbs of filaments passing through the noose. A noose with lower internal friction in the noose knot will tend to have a higher noose efficiency.

One instrument for inserting anchor 12 into a hole drilled in bone is illustrated in FIG. 2. Driver 40 has a distal end 42 removably insertable into passage 16. Driver 40 is cannulated in this construction and has a lumen 44 with an optional threader filament 46 that passes through noose 30. Use of a threader filament is optional, but may be desirable when noose 30 is spaced only a short distance from filament engagement feature 18, in other words, when noose 30 is initially positioned close to or inside of anchor 12.

In one procedure according to the present invention, anchor 12 is shown fixated within bone B, FIG. 3, after driver 40 has been removed, in a hole 50 spaced at a desired distance from tissue T to be repaired. Noose 30 is in an initial open configuration. Threader filament 46 has a sufficient length to have both a threader loop 52 on a first limb, and a graspable portion on a second limb 54, extend proximally above skin S while a mid-portion of threader filament 46 is slidably associated with noose 30.

Continuing with this exemplary procedure, a second filament 60, FIG. 4, is threaded through tissue T using a suture passing instrument, a needle, or other tissue-penetrating technique chosen by a surgeon. Both free filament limbs 62 and 64 are brought together, typically above skin S, or at least outside of a joint space, and passed through threader loop 52, FIG. 5. Threader limb 54 is then pulled to thread both second filament limbs 62 and 64 through noose 30 as illustrated in FIG. 6 while noose 30 is in the initial open configuration. Alternatively, free filament limbs 62 and 64 are passed directly through noose 30 without using a threader filament.

When there is high noose efficiency, a light tug is sufficient to collapse noose 30 on the filament limbs 62 and 64 as shown in FIG. 7 to provide initial tensioning on the surgical filament snare assembly 10. Generally, a higher noose efficiency can be utilized when one or more free filament limbs are threaded directly through noose 30 without using a threader filament, or are threaded using a tube or threader device such as shown in FIGS. 13-14B below.

After initial or pre-tensioning of free filament limbs 62 and 64, FIG. 7, tension is released on limbs 62, 64 and a slidable stopper knot 70, FIG. 8, is tied by the surgeon on limbs 62, 64 above skin S. An enlarged view of one construction for stopper knot 70 a, FIG. 8A, shows a half hitch with an extra throw or turn, also known as a double overhand knot. A simple knot such as a single half hitch or overhand knot may be sufficient for some situations. Other suitable, more robust surgeon slidable knots with higher load capacity include the Tennessee Slider described in the Arthroscopic Knot Tying Manual (2005) available from DePuy Mitek, as well as the slidable, lockable knot by Wenstrom, Jr. in U.S. Pat. No. 6,767,037. Alternatively, a mechanical locking mechanism may be utilized where overall profile is not critical, especially away from a joint or other articulating surfaces.

Stopper knot 70 is advanced, typically using a knot pusher, until it contacts noose 30, FIG. 9. Tension generated between tissue T and anchor 12, alone or together with pulling on one of the filament limbs 62 or 64, causes noose 30 to further collapse, FIG. 10, and strangulate the filaments. Stopper knot 70 augments the strangulation by transferring all tissue-generated tension on the stopper knot to the noose 30 and preventing slippage of filament limbs 62, 64 into the noose knot. Accordingly, a self-cinching mechanism is created which inhibits loosening of the filaments. Tension can be increased incrementally in a ratchet-like effect by further advancing the stopper knot or pulling on one of filament limbs 62, 64.

Once satisfactory tissue tension has been achieved, one or more half hitches may be added to stopper knot 70 to fortify the loading capacity on the stopper knot and reduce the risk of loosening under adverse conditions. By comparison, conventional sliding knots typically are reinforced by at least two or three reversed half hitches placed on alternating posts. Due to the self-cinching effect of the present invention, fewer overall hitches or other knots are needed for stopper knot 70 to meet or exceed the load performance relative to conventional knot systems. The present invention thereby accomplishes a lower overall knot profile to handle a given load. Limbs 62, 64 are trimmed as desired. The stopper knot also minimizes fraying of the filament ends over time.

Preferred materials for filaments 14 and 60 include various surgical sutures, typically size 0 to size 5, such as Orthocord™ suture commercially available from DePuy Mitek, and Ethibond™ suture available from Ethicon. Orthocord™ suture is approximately fifty-five to sixty-five percent PDS™ polydioxanone, which is bioabsorbable, and the remaining percent ultra high molecular weight polyethylene, while Ethibond™ suture is primarily high strength polyester. The amount and type of bioabsorbable material, if any, utilized in the first or second filament is primarily a matter of surgeon preference for the particular surgical procedure to be performed.

While the same type of suture, even identical suture, can be used for both first, noose filament 14 and second, tissue filament 60, a suture having a lower abrasive property at its surface may be preferred by some surgeons for second filament 60. The lower abrasive property can be achieved by a larger diameter, a softer composition, a softer braid, plait or strand pattern, or a combination of such characteristics.

The nooses illustrated in FIGS. 1-6 above have been described as having a single opening through which one or more free filament limbs are threaded. A simple half hitch or overhand-type “pretzel”-like knot is illustrated in FIG. 11 for noose 30 c having multiple useful openings 80, 82 and 84. Side openings 80 and 84 are formed by minor loops 81 and 83 of the half hitch knot in first filament limbs 36 c, 38 c while central opening 82 is formed by the major loop. Free filament limbs 62 c and 64 c are shown in FIG. 12 extending through side opening 80 and central opening 82, respectively, although other combinations and permutations, such as using side openings 80 and 84, or central opening 82 and side opening 84, are also effective. Utilizing different areas or regions of the noose knot significantly increases effective strangulation and gripping on the free filament limbs. It is expected that utilizing multiple openings in the noose knot also minimizes any dependence of load carrying capacity on filament compliance characteristics. A simple, single half hitch stopper knot 70 c is also illustrated in FIG. 12.

While two or more threader filaments, or careful, potentially tedious manipulation by a surgeon, could be utilized to achieve the configuration shown in FIG. 12, an alternative technique which avoids inadvertent noose collapse is shown in FIG. 13. Tubes 90 and 92 have outer diameters suitable for sliding into the side openings formed by loops 81 and 83. Filament limbs 36, 38 c are shown engaged with anchor 12 c. Tubes 90 and 92 define passages 94 and 96, respectively, through which free filament limbs 62 c and 64 c are threaded. Tubes 90 and 92 are then disengaged from noose 30 c and drawn proximally along filament limbs 62 c and 64 c until they can be removed and discarded appropriately.

Double-barrelled threader device 100, FIG. 14A, has two threader tubes 102, 104 which are joined together with a handle 106 and provide an even easier technique. In one construction, device 100 is molded as a monolithic unit using a polymer material. Tubes 102, 104 have internal lumens 108, 110, respectively with openings at both ends as well as slots 112, 114, respectively, which also run the entire length of tubes 102, 104. During use, tubes 102, 104 are placed through loops 81 d, 83 d, FIG. 14B, formed from first filament limbs 36 d, 38 d, and free filament limbs 62 d, 64 d are inserted through lumens 108, 110. Thereafter, limbs 62 d, 64 d are simply lifted through slots 112, 114 to remove the fully-threaded filaments from the device 100. One or more additional such tubes can be formed and utilized as desired. Also, the tubes 102, 104 can be formed as “C” or “U” shapes in cross-section, with wider slots than illustrated.

There are a number of other configurations of snare assemblies according to the present invention which have one or more adjustable-length noose support stems or limbs that enable the noose to be retracted as desired toward an anchor. These configurations provide an additional level of control over the final filament positions and tensions. Snare assembly 120, FIG. 15, has a noose 124 formed at one end of a first filament 122 with a stem section 126 extending into anchor 130 to pass through ratchet-like one-way gate or clamping mechanism 132. The remainder of filament 122 serves as a limb 128, also referred to as a stem tail. Some examples of one-way mechanisms are disclosed in U.S. Pat. No. 5,702,397 by Goble et al., for example, which allow filament movement in only one direction.

As illustrated in FIG. 15, anchor 130 is fixated in bone B. A second filament 134 is passed through tissue T and has free limbs 136 and 138 passed through noose 124, initially positioned outside of a joint space surrounding tissue T. Limb 128, also positioned outside of the joint space, is pulled to retract noose 124 toward mechanism 132. Typically, the noose 124 is collapsed, limb 128 is trimmed, and then a procedure similar to that illustrated for FIGS. 7-10 above is utilized.

Snare assembly 140, FIG. 16, has first filament 140 having a noose 144 tied with two stem limbs 146 and 148 extending into anchor 150. In this construction, anchor post 152 serves as a filament engagement feature to slidably attach filament 140 to anchor 150. Filament stem tail limbs 154, 156 extend out of a joint space, together with noose 144 in an initial configuration. Second filament 160 is passed through tissue T and then free limbs 162, 164 are passed through noose 144 outside of the joint space.

In the procedure illustrated in FIG. 16A, limbs 154 and 156 of first filament 142 are also passed through noose 144 and then pulled to collapse noose 144 about all four limbs 154, 156, 162 and 164 and to retract noose 144 toward filament engagement post 152. One or more sliding knots are tied on limb pair 154, 156 of the stem tails to adjust the proximity of noose 144 to the anchor 150 and then a simple knot is tied on free limbs 162, 164 to adjust final tension on tissue T, although other combinations and permutations can be utilized within the scope of the present invention. Typically, the sliding knots are finished with one or more half hitches to “seal” or complete the fixation.

Snare assembly 170, FIG. 17, utilizes a single filament 172 both to secure noose 174 to anchor 180 and to tension tissue T. Stem limbs 176, 178 pass into anchor 12 and slidably around filament engagement post 182 to emerge from anchor 180 as tail limbs 184, 186 which are initially kept out of the joint space, along with noose 174, when anchor 180 is fixated in bone B. In some constructions, anchor post 182 is an eyelet or a pulley pin. Free tail limbs 184, 186 are passed through tissue T, in the same or different places or regions, and then through noose 174. Noose 174 is collapsed and pulled into the joint space by applying light tension to one, or preferably both, of the tail limbs 184, 186. A simple stopper knot is tied between tail limbs 184, 186 and pressed against the noose 174 while tensioning the limbs 184, 186 to place a desired amount of tension on tissue T. The fixation is finalized by placing one or more half hitches against the stopper knot at noose 174.

Snare assembly 190, FIG. 18, has functional similarities to snare assembly 120, FIG. 15, but achieves ratchet-like noose retraction without one-way gate or clamping mechanisms. Filament 192, FIG. 18, has a noose 194 with a stopper knot 196 at its terminal end to prevent pull-through and to resist fraying. A sliding knot 198 enables loop 200, having loop limbs 202 and 204, to be shortened toward anchor 205 when post limb 206 is pulled. Loop 200 passes around anchor saddle or post 207. This and other adjustable loop, sliding knot configurations are described in more detail below in relation to FIGS. 21-27.

Snare assembly 310, FIG. 19, includes a first filament 302 with a noose 304 and a loop 306 which is fixed in length, the overall length of filament 302 being subject to full collapse of noose 304. A second filament 316 has a terminal end 318, a sliding knot 322 retained at the distal end of anchor 312, a post limb 320, and an adjustable loop 324 formed by limbs 326, 328. This configuration is described in more detail below in relation to FIG. 28.

While most of the embodiments herein have been described in relation to securing one or two filament limbs passed through a single place or region in a tissue T, this is not a limitation of the invention. Snare assembly 210, FIG. 20, has a first filament 211 with a noose 212 through which pass free limbs 214, 216 and 218, 220 of second and third filaments 222 and 224, respectively. Noose 212 is engaged by stem 213 with anchor 215. Filaments 222 and 224 pass through tissue regions R1 and R2, respectively. Multiple regions of a tissue, and potentially multiple types of sutures or other filaments, can thereby be secured using a single snare assembly according to the present invention.

One arrangement of the filament 192 for snare assembly 190, FIG. 18, is illustrated in FIG. 21 for snare assembly 190 a. Noose 194 a is formed merely by creating opening 232 in region 230 of filament 192 a and passing filament 192 a through itself. Loop 200 a and sliding knot 198 a are formed thereafter on post limb 206 a. In this arrangement, any tension applied on stem 234, such as by pulling post limb 206 a, not only collapses noose 194 a to strangulate objects passing through noose 194 a, but also binds the portion of filament 192 a passing through opening 232 upon itself. In other arrangements, a half hitch or other simple knot is tied at filament region 230, and filament 192 a is then looped through that simple knot. Stopper knot 196 a such as a simple half hitch will prevent the terminal end from fraying or opening up, especially if a braided filament such as Orthocord™ suture is utilized for filament 192 a.

An example of steps for manufacturing snare assembly 190, FIG. 18, utilizing suture as filament 192 is as follows. Tie stopper knot 196 and trim the tail of the terminal end. Loop the suture and pass it through itself in close proximity to the stopper knot 196 to achieve the noose arrangement illustrated in FIG. 21, or tie a second half hitch in close proximity to the stopper knot and pass the suture through the half hitch to create the noose 194, FIG. 18. A thin mandrel or other object such as a pin may be placed through noose 194 to maintain patency. Sliding knot 198, such as a bunt line half hitch knot, is tied in close proximity to the noose 194 and the suture is placed in sliding engagement with feature 207 of anchor 205. Sliding knot 198 is then dressed or finalized as desired.

Conventionally, rotator cuff lateral row fixation involves spanning a suture bridge from medial anchors. Sutures are fixated with knotted or knotless anchors at the lateral row. Unthreaded anchors suffer more often than threaded anchors from anchor pull out, and suture slippage may occur at relatively low loads in many conventional procedures regardless of anchor type.

A presently preferred technique for rotator cuff double row repair is illustrated in FIGS. 22-27 utilizing the snare assembly of FIG. 18. Medial row anchor 240, FIG. 22, is shown already embedded in bone B having cuff tissue T fixated at the medial row with suture 242. Preferably, a threaded anchor is utilized for anchor 240, and may be the same type of anchor as anchor 205. Free suture limbs 244 and 246 are retracted out of the joint space, shown in FIG. 22 as extending beyond skin S. Threaded anchor 205, FIG. 23 is then placed as a lateral row anchor in hole H independently of the medial row fixation. At this stage, collapsible loop 200 is long enough to enable sliding knot 198 and noose loop 194 to extend out of the joint space.

Suture limbs 244, 246 from the medial row are then passed through noose 194, FIG. 24, preferably utilizing one of the threader devices described above. Any tension on suture limbs 244, 246 will collapse noose 194 around them. The size of the threader tube may be selected to limit the migration of noose 194 from sliding knot 198. Post limb 206 is then tensioned, FIG. 25, in the proximal direction indicated by arrow 250 to retract sliding knot 198 into or in close proximity to anchor 205 and to place initial tension on suture bridge 258.

A simple knot such as a half hitch is then tied between suture limbs 244, 246 and pushed down against noose 194, FIG. 26, as sliding knot 260 while limbs 244 and 246 are pulled to further tension suture bridge 258 as desired. As second or more half hitches 262, FIG. 27, are added after suture bridge 258 has been properly tensioned to permanently lock the repair and the ends of suture limbs 244 and 246 are trimmed. Because a single noose can handle multiple pairs of sutures as described above in relation to FIG. 20, additional suture bridges can be secured from multiple medial anchors as desired.

Adjustable suture snare assembly 310, FIG. 28, has a suture anchor 312 and a closed, fixed-length loop 306 of a first material 302, which has a noose 304 tied at one end. A half hitch “pretzel”-like knot 305 is shown in this construction. Loop 306 is captured by, in other words, is connected to, a second filament 316 having a terminal end 318, a post limb 320, a sliding bunt line half hitch knot 322, and an adjustable loop 324 with loop limbs 326 and 328. Second filament 316 may be considered as part of an adjustable filament engagement feature of anchor 12, because filament 316 connects noose 304 to anchor 12. In one construction, suture anchor 312 is similar to the cannulated suture anchor disclosed by Cauldwell et al. in U.S. Patent Application Publication No. 2008/0147063, incorporated herein by reference. In anchor systems utilized according to this sliding knot configuration of the present invention, however, it is not necessary to have a post-like suture-engaging member or other occluding element over which one or more sutures or suture limbs pass to serve as a restriction to proximal movement; in many constructions, it is sufficient to have a restricted opening 346 to prevent withdrawal of knot 322.

Suture anchor 312 has a proximal end 330 and a distal end 332 with opposed distal arms 334 and 336 defining cut-out 338 between them. Passage 340 is an inner lumen which runs from proximal end 330 to distal cut-out 338. Although knot 322 is shown extending beyond cut-out 338 in FIG. 28 for purposes of illustration, knot 322 preferably is seated against restricted opening 346 between arms 334 and 336, or otherwise maintained at the distal end 332 by a cavity or other feature, during insertion of snare assembly 310 into a patient to minimize interference by the knot 322 with the bone-engaging feature 342, or other exterior surface of anchor 312, and the bone in which suture anchor 312 is fixated.

One or more bone-engaging features 342, such as the helical thread illustrated in FIG. 28 or other features such as teeth, ridges, or other protrusions, are formed on the exterior of anchor 312 to enhance fixation in bone. Threads such as found on the Healix™ anchor available from DePuy Mitek Inc. are desirable. In another construction, the suture anchor rotates to toggle into bone at its proximal end to minimize withdrawal. In a number of constructions, a hole is formed in bone prior to anchor insertion; in other constructions, a suture anchor is inserted directly into bone. Further, one or more passages or channels may be formed on the exterior of the suture anchor, such as channel 344 illustrated in phantom, FIG. 28, traversing bone-engaging element 342.

It is a matter of surgeon preference whether a terminal end 318 is kept at a length sufficient to lie against the exterior of at least one bone-engaging feature 342 to be trapped against bone during insertion, or is trimmed to a shorter length. Further, a restriction such as restricted opening may be defined at least in part by engagement with bone when anchor 312 is fixated in bone to prevent knot 322 from moving with post limb 320 when tension is applied to post limb 320.

One or more such distal extensions or other protrusions may be provided, similar in some constructions to Cauldwell et al. cited above or to U.S. Pat. No. 7,381,213 by Lizardi, also incorporated herein by reference. In yet other constructions, a cylindrical or otherwise circumferential cavity, bowl or countersink feature is provided at the distal end of the anchor to seat the knot 322 during insertion and fixation.

Slidable knot 322 has been described as a bunt line half hitch knot in some constructions, but other suitable knots will be readily apparent to those of ordinary skill in the suture tying art after reviewing the present invention. The term “slidable” as used herein is intended to include slidable, lockable knots as well as slidable knots, such as those described in the Arthroscopic Knot Tying Manual (2005) available from DePuy Mitek, as well as the slidable, lockable knot by Wenstrom, Jr. in U.S. Pat. No. 6,767,037.

Thus, while there have been shown, described, and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions, substitutions, and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the invention. For example, it is expressly intended that all combinations of those elements and/or steps that perform substantially the same function, in substantially the same way, to achieve the same results be within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated. It is also to be understood that the drawings are not necessarily drawn to scale, but that they are merely conceptual in nature. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

Every issued patent, pending patent application, publication, journal article, book or any other reference cited herein is each incorporated by reference in their entirety. 

What is claimed is:
 1. A surgical filament snare assembly, comprising: an anchor capable of being fixated in bone and having at least one passage and a filament engagement feature, the filament engagement feature being located at a distal end of the anchor and the at least one passage extending from a proximal end of the anchor and toward the filament engagement feature; and a first filament having a noose on a first portion of at least a first limb and having a second portion extending into the passage to engage the filament engagement feature of the anchor, the noose capable of receiving at least one end of a free filament limb and strangulating it when tension is applied to at least one of the free filament limb and the noose, wherein an entire inner perimeter of a closed loop formed by the noose is remote from the filament engagement feature.
 2. The assembly of claim 1 wherein the noose is retractable toward the anchor.
 3. The assembly of claim 1 wherein the noose is formed from at least one half hitch.
 4. The assembly of claim 1 wherein the noose includes a hangman's-type knot.
 5. The assembly of claim 1 further including at least one tube capable of being removably inserted into the noose to provide a passage for the end of the at least one free filament limb.
 6. The assembly of claims 5 wherein each tube is slotted to facilitate removal of the free filament limb from the tube.
 7. The assembly of claim 3 further including at least two tubes capable of being removably inserted into different loops of the half hitch to provide passages for two ends of free filament limbs.
 8. The assembly of claim 7 wherein the tubes are joined together and have at least one handle for manipulating the tubes.
 9. The assembly of claim 8 wherein each tube is slotted to facilitate removal of the free filament limbs from the tubes.
 10. A surgical filament snare assembly, comprising: an anchor capable of being fixated in bone and having at least one passage extending from a proximal end of the anchor and toward a filament engagement feature located at a distal end of the anchor; a first filament having a noose on a first portion of at least a first limb and having a second portion connected to the filament engagement feature of the anchor, the second portion extending into the passage to engage the filament engagement feature and out of the passage at the proximal end of the anchor after engaging the filament engagement feature; and at least a first free filament limb which is capable of being passed through tissue to be repaired and having at least one end passable through the noose to enable incremental tensioning of the tissue after the anchor is fixated in bone, the noose strangulating the free filament limb when tension is applied to at least one of the free filament limb and the noose.
 11. The assembly of claim 10 wherein the first free filament limb is a length of a second filament.
 12. The assembly of claim 11 wherein the second filament includes a second free filament limb which is also passable through the noose such that the tissue is captured between the first and second free filament limbs.
 13. The assembly of claim 10 wherein the first free filament limb is a length of the first filament.
 14. The assembly of claim 13 wherein the first filament includes a second free filament limb which is also passable through the noose such that the tissue is captured between the first and second free filament limbs.
 15. The assembly of claim 10 wherein the noose is formed from at least one half hitch.
 16. The assembly of claim 10 wherein the noose is retractable toward the anchor.
 17. A surgical suture snare assembly, comprising: an anchor capable of being fixated in bone, the anchor having a proximal end, a distal end, at least one passage extending between the proximal and distal ends, a suture engagement feature located at the distal end, and a first side and a second side extending between the proximal and distal ends, the first side located on one side of the filament engagement feature and the second side located on an opposite side of the filament engagement feature; and a first suture having a noose and a first limb and a second limb extending from the noose, the first and second limbs both extending initially from the first side of the anchor and to the second side of the anchor, wherein at least one of the first and second limbs is capable of being passed through the tissue to be repaired and having at least one end passable through the noose to enable incremental tensioning of the tissue after the anchor is fixated in bone, the noose strangulating the respective first or second limb when tension is applied to at least one of the free suture limb and the noose. 